In well drilling processes, wellbores are commonly cemented, where the annulus between the casing and the wellbore wall is filled with cement, forming a cement sheath. High internal pressure may expand the casing and the cement sheath, which causes tensile stress on the cement sheath. Generally, cement materials are brittle, and the compressive strength is greater than the tensile strength of cement formations. Accordingly, the increased tensile stress on the cement sheath caused by the internal pressure may cause damage, such as cracking or fracture, to the cement sheath, which may lead to undesired leaking.
The damage to the cement sheath described in the preceding paragraph may be worsened by the high density of cement materials commonly used as cement sheaths in wellbores. Specifically, greater density cement materials are used in wellbores because they have less voids in the cement structures, which results in less migration of hydrocarbons from the geological formation into the well. However, the low number of voids in the cement material can increase the brittleness of the cement material, which may lead to damage of the cement structure when pressure is applied to the cement structure.